Synchronized phasor (synchrophasor) measurement unit (PMU) has become an important measurement component in a power system and can provide high precision voltage and current phasors and frequency which are synchronized with an absolute time reference. The applications of PMU have been well recognized for real time dynamic monitoring, operation and control of the power system.
Traditionally, a power system may be monitored through a combination of non-synchronized measurements, for example, generator/load power and voltage magnitudes are fed into a software model, and then the complete voltage angle and magnitude information for each bus for specified load and generator real power and voltage conditions are calculated. However, these quantities can be calculated directly using PMU.
With the growing demand for synchrophasor measurement technology, a standard related to this measurement has been set up by IEEE to ensure the interoperability of devices from different vendors since 2005. There are now many PMUs in compliance with the standard in the market. However, as the standard is only designed for steady-state measurement and cannot meet further demand for dynamic-state measurement (such as during power swing, phase angle change, frequency consecutive change and even fault disturbance) with a lack of comparability and interoperability among synchrophasors measured by different products, some vendors have begun to use their enterprise standard defined by themselves. Based on the new demand, the IEEE and IEC have been working together to establish a new standard including dynamic-state measurement. This standard may be released soon.
A synchrophasor measurement method and device applicable to both the steady-state measurement and dynamic-state measurement in a power system is thus needed. Such a method and device is able to comply with the new standard that covers the dynamic-state measurement in the power system.